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Separation of Red (Y 2 O 3 : Eu 3+ ), Blue (Sr, Ca, Ba) 10 (PO 4 ) 6 Cl 2 : Eu 2+ and Green (LaPO 4 : Tb 3+ , Ce 3+ ) Rare Earth Phosphors by Liquid/Liquid Extraction Abstract: A novel process for separation of red (Y 2 O 3 : Eu 3＋ ), blue (Sr, Ca, Ba) 10 (PO 4 ) 6 Cl 2 : Eu 2+ and green (LaPO 4 : Tb 3＋ , Ce 3＋ ) fine tricolor phosphor powders was established. First, the green phosphor was extracted and separated from three phosphor mixtures in heptane/DMF(N, N-Dimethylformamide) system using stearylamine or laurylamine (DDA) as the cationic surfactant. Then, after being treated with 99.5% ethanol, the blue and red phosphors could be separated in Heptane/DMF system in presence of 1-octanesulfonic acid sodium salt as the anionic surfactant. Satisfactory separation results have been achieved through two steps extractions with their artificial mixtures. The grades and recovery of separated products reached respectively as follows: red product was 95.3% and 90.9%, blue product was 90.0% and 95.2%, and green product was 92.2% and 91.8%.

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The polyaniline/copper oxide (PANI/CuO) nanocomposite was prepared by mixing solutions of polyaniline and copper oxide nanoparticles in dimethyl sulfoxide (DMSO). The synthesized polymer nanocomposites were characterized by X-ray powder diffraction (XRD), scanning electron microscope (SEM) and UV-visible spectroscopy. The characteristic peaks in XRD and UVvisible spectra confirmed the presence of CuO in the polymer structure. SEM images indicated morphological changes in the composite matrix as compared to the pristine PANI. The DC conductivity measurements were performed using two-probe method for various temperatures. AC conductivity and dielectric response of the composites were investigated in the frequency range of 10 2 -10 6 Hz using LCR meter. Dielectric permittivity 0 ðwÞ and dielectric loss factor 00 ðwÞ were investigated. It was observed that 0 ðwÞ and 00 ðwÞ decrease with increase in frequency at all temperatures. At a particular frequency it is observed that both 0 ðwÞ and 00 ðwÞ increase with increase in temperature. It was also observed that AC conductivity increased with increase in frequency and temperature.

A novel process for separation of red (Y 2 O 3 :Eu 3+ ), blue(BaMgAl 10 O 17 :Eu 2+ ) and green (CeMgAl 10 O 17 :Tb 3 ) rare earth fluorescent powders was proposed. At first, the blue powder can be extracted selectively from an aqueous solution using a chelating collector 2-thenoyltrifluoroacetone (TTA) dissolved in heptane at alkaline pH condition, then, chloroform was used for extracting the green powder into organic phase. The red phosphor remains in aqueous phase with potassium sodium tartrate depressant (PST). Therefore, three phosphors can be separated successfully from their artificial mixtures by liquid/liquid extraction, and grades and recovery of separated products reach respectively as follows: red is 96.9% and 95.2%, blue is 82.7% and 98.8%, green is 94.6% and 82.6%.

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